Electric oscillator



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H. G. coRDEs ELECTRIC OSCILLATOR Filed May 10 1917 4 Sheets-Sheet l -INVENT0R WITNESSES H. G. CORDES ELECTRIC OSCILLATOR Dec. 25, 1923.

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INVENTOR Dec, 25, 1923. 1,478 %38 v H. GpCORDES ELECTRIC OSCILLATOR Filed May 10 1917 48heets-Sheet s WITNESSES INVENTOR @em25Q1i923. 11,47,638

H. G. CORDES ELECTRIC OSCILLATOR Filed May 10 1917 4 Sheets-Sheet 4 FIG.I?.

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. ELECTRIC OSCILLATOR. v

Application fil ed. ma 'io,

Toall whom it may concern:

Be it known that I, HENRY G..CORDES,' a citizen of the United States, residing "at Bremerton, ,in the county of Kitsap and State of Washington, have invented new and useful Improvements in an Electric Oscillator. m I

My invention-relates to improvements in" arrangements for starting, sustaining, utioscillations of a direct current ;c ure greater stability of the apparatus, to

ada pt aiLarc oscillator to the production of variable fiquency oscillations for radio "dothe p'loduction of imit-current is .at least telephony and to efliciently transform the potential of direct current energy by means of oscillating current.

These improvements are attained by applying. a principle well known in the pro;

ductlonofoscillationsinanechanical devices electricaloscillations. My invention can considering the direct current are oscillator as the basis of my improvements. My improvements ertain to class 2 oscillations which are de ned by the committee onstandardization for 1915 of the Institute of Radio Engineers as those oscillations in which the amplitude of the oscillation circurrent, tut in which the direction of the current thruthe arc is never reversed. In other words, in this class ofoscillations. the arc acts as an electric check valve. i

A class 2 oscillationinvolves three circuits and two time intervals. The circuits will bereferred to as the direct current charging circuit, the direct current are circuit and the discharge circuit. The time intervals will be referred to as the primed and unprimed intervals. During the primed interval'current flows through the arc and during the unprimed interval no current flows through the arc. The direct current are and discharge circuits are only closed'during the primed interval. With the usual large inductance in series with the direct current source the direct current amplitude varies a little be best explained by Fig. 3 shows equal to the direct.

1917. serial no. names.

and consists of an oscillating current of comparatively small amplitude superposed upon a direct current. The discharge circuit consists of a capacltance discharging through ,aninductance; the inductance may be either in series withthearc or in series with the capacitance across the direct current line.

The potential of the capacitance varies practically as a linear function of the time during the unprimed interval or period 1 while the potential varies as a sinusoidal function of thel-timeduring the primed period of each cycle. rent is also a straight line and a damped sine. wave. Oscillations having the ohar-- acteristics above described will be referred .to by the general'term linear-sinusoidal oscillations.

During the primed period electromagnetic energy is stored in the direct current arc-circuit inductance while during the unprimed period the discharge circuit capacitance is charged simultaneously with the discharge of this energy and the energy due to the flow of direct current during the unprimed period.

:The drawings fication and the forming part of specifollowing explanations of the'figuresof the drawings will disclose my 7 improvements. v F1g. 1 shows a class 2 are oscillator and an additlonal arc in serles, to which Is con- Similarly, the graph of the curnected' my characteristic circuit arrangement.- Fig. .2 is a modification of Fig. 1. an arrangement in which the arc is placed in a vacuum and oscillations are diflic'ult to start. Figures 4 and 5 show arrangements to facilitate starting. Figures 6, 7, 8 and 9 show -modifications of parts of Figures 4 and 5. Figures 10 and 11 show a practical arrangement for starting which is an essential feature of my improvement. Figures 12 and 13 show arrangements for varying the frequency of the oscillations. Figures 14 and 15 show a direct current potential transformer.

refer to similar parts.

Tn Fig. 1 consider the anode T and cathode K of the arc TK the direct current source E,.the inductance Figures 16 and 17 show electro-mechanical arrangebe given. Similar short circuited. Then T, the arcA-T, the capacitanceS and inductance L constitute an arc oscillator of the prior art. Assume that class 2 oscillations are flowing in the circuits. The frequency- 1E5 between-A and T and'thus form the arc TK.' The potenti'alof -s which ggnited 'Fi 1 are here replaced bythe-mercury arc va ve V. It is well known that with a given 7 voltage between A and K current will not fiow from A to K, but if a spark assesfrom T to K then the path from A 'to K becomes 70 conductive due to ionization by collision ofthevapor. 4 1 It. is obvious that if an oscillating current of proper frequenc flowsin the priming circuit TK-P- that linear-sinusoidal 75 oscillations will result'in L and 'S, the arc being primed at the proper instant during each cycle, by the priming circuit in which there is assumed to be enough voltage to spark from T to K and K to T during each so cycle as is the case in the discharge of a ch11 the arc AT in the production of class 2denser acrossa spark-gap inseries with'im oscillations, is not able to reignite the arcs e A.T and TK in series. P is large comared to L and S is large compared to C.

he current in TK charge circuit A- K--LS. The oscillations in the T-K-P-C circuit serve as a pilot spark for reignition or closing of' the discharge circuit. The frequency of the discharges in the discharge circuit therefore depends upon the natural period of the tionsas a particular type of linear-sinusoidal oscillations in which the arc has tWO A electi ooeswntermmals and a drooping volt 4 ampere characteristics-1Qreignitlon depends upon the potential of the capamtancrls) of arc oscillator. -C is small and the potential is hi h compared to the dis-v ductance. 4

The arc is un rime'd' as itsis in a, class 2 I f linear-sinusoidal oscilla- 85 tions areassumed to exist in L and S, then the oscillating current in the priming circuit would be sustained by a transfer of energy from Lto P.

This arrangement will'therefore not oper- 90 ate because linear-sinusoidal oscillations can not'be produced unless oscillating current flows in the priming circuit and oscillating current cannot flow in the priming circuit unless there are linear-sinusoidal oscillations 05 in L and S from which the priming circuit can receive its energy. In a number of mechanical devices analogous conditione exist. F or example, the

pendulum of a clock will not swing unless 100 the escapement-operates, but the escapement will not operate unless the pendulum swings.-

the discharge circuit. The presence, oftliefi irnethwrgple is the as engine; the pispriming circuit will render the frequency of 4c the linear-sinusoidal oscillations more independent of fluctuations in the amplitude of the direct current. I

Fig. 2 is a modification of Fig. 1. An

auxiliary direct current "arc circuit 3'2 l-.T.-K is added. This auxiliary direct current are circuit and the priming circuit, which becomes a discharge circuit, produce class 2 oscillations. The auxiliary arc circuit prevents inverse current through the arc T-K and also provides for two sources of energy supply to the priming circuit, viz; from L to and from the auxiliary direct current are circuit to the priming circuit.

The frequency of the priming circuit can be varied by changing the amplitude of the auxiliary direct current by means of the. rheostat :4 and this will, change the frequency of the linear-sinusoidal oscillations in L-S. The large ratio of. P to C will render the frequencyof the class 2 oscillations in the priming circuit comparatively constant.

I In Fig. 3, E, I, L, S, P and C have the same relations as in Fig. 1. The two arcs of tem and slide valve mechanism are trigger 1'15 arrangements whose failure to operate will 7 stop the How of energy from the source.

Fig. 4: shows an auxiliary arrangement to make Figure 3 operate. In this figure L is divided into two sections, -'7 and 8.' P is coupled to section 7. The inductances, 8 and 9, constitute an oscillation transformer "of variable coupling; The terminals, 10 and 11,- are connected to a source of alternating currentor sustained oscillations,"thus making 9 the primary of the oscillation transformer. A rheostat 5 is placed in series with the direct current circuit.

To operate this arrangementclose switch 6 and short circuit T --K by tilting the valve discharge circuit quency equal to the natural frequency of the priming circuit on and 11. This will induce constant amplitude oscillations in the A--K-L-S after the starting transient has disappeared. The

maximum amplitude of the oscillating current in the discharge circuit must remain less than the direct current amplitude or the valve.

will become unprimed. Close and open T-K by tilting the valve; if enough energy is transferred from L to P to maintain an oscillating current across the ga T-K in the priming circuit then the coupling of the oscillation transformer is increased until the maximum amplitude of the oscillating current in the discharge circuit is greater than the amplitude of the direct current and the result will be linear-sinusoidal oscillations in L and S. The linear-sinusoidal oscillations are initiated the instant that the resultant c'urrent thru V becomes zero. Resistance is now gradually removed from the direct current circuit by means of 5 and at the same time the coupling of the oscillation transformer is gradually decreased so that the amplitude of the linear-sinusoidal oscillations remains. practically constant while the energy supply is gradually transferred from the alternating. current circuit to the direct current circuit.

tions.

Tf"the.current in-the ipriming circuit is too weak, to sustain the linear-sinusoidal oscillations then only a series of linear-sinusoidal oscillations of decreasing frequency will take place in L-S when the maximum amplitude of the oscillating current in L-SV becomes large enough to unprime the valve provided the potential induced in 8 by the alternating current flowing thru 9 is small compared tothe potential required to produce a spark from A to K and provided the value of the potential of source E and the resistance 5 are less'than the critical value for stability. This-series of linearsinusoidal oscillations is the .result of the dissipation of the electromagnetic energy stored by the direct current in the inductance T. It is known thatif both the potential of source E and the resistance 5 be made large enough that :oscillationswill take place in Fi 4 when the priming circuit P-C is omitted; the ob]e'ct of adding thepriming circuit beingto produce oscillations from a source of lower potential, reduce energy dissipated in 5 and secure oscillations ofmore constant frequency.

' Fig. 5 is similar to Fig. 4-, except an intermediate oscillatory circuit L-Q-Z is introduced. This circuit is conductively coupled to the discharge circuit. "Both the circuit which is thus This constitutes one method of starting linear-sinusoidal oscillarequired the loss of energy to be transferred to the discharge circuit as linear-sinusoidal oscillations. Energy is transferred from the latter to the intermediate circuit which then becomes the secondary oscillatory circuit. The secondary circuit transfers energy to the priming indirectly coupled to the discharge circuit.

. Two practical diiiiculties arise in the arrangements .of- Figures 4 and 5; a suitable starting circuit cannot readily be provided except in a laboratory and, secondly, if the valve V has a vacuum and gas suitable for the efficient production of radio frequency oscillating current, priming gap T- t deionizes so rapidly that it constitutes a high effective resistance in the priming circuit, which renders it difiicult to transfer enough energy from L to P to sustain theoscillatory current in; the primin circuit.

then it is found that the j The latter difiiculty will be dealt with first.

The function of the starting band on a mer-. cury vapor lamp is well known. The presence of a starting band or positive pole near the cathode'while being positively charged with respect to the cathode reduces the potential between the anode and the cathode for the main For convenience in explaining my invention this phenomenon will be considered due to an arc-priming discharge in a discharge circuit comprising the band, the capacitance between the band and the rarefied gas, the rarefied gas which becomes ionized, the cathode, and, the capacitance beits discharge to be initiated.

tween the cathode and the band; this circuit has negligible inductance hence the discharge is of short duration and the maximum instantaneous current is large thus producing maximum ionization to initiatethe main discharge with the minimum expenditure of energy. j t ig. 6 shows the valve/V with two starting bands, 14 and 15, adjacent to the priming electrode T and cathode K. This reduces the potential nating current are between T and K.

Fig. is a modification of Fig. 6 and involves a change H1 the priming circuit... band'15 is used, and

Here, only one starting its required to maintain an alterment the oscill'atingcurrent thru P-C will spark from T to K, but not from K to T; be-

' cause the voltage drop thru valve 16 in the direction of the arrow is less than the potential required to spark from K to T.- The gap T-K thus becomes a uni-directional current spark gap and 16-is a by-pass for inverse current thru T-K.

Figure 8 shows another modification of the valves and priming circuit of Fig. l. Increasing'the potential between the priming terminal T and cathode K to a sufficiently high value, increasing positively on T with respect to K, will decrease the potentialrequired between anode A and cathode K to initiate a discharge. from A to K. In this arrangement the valve is prirned with displacement current flowing thru the wall of V from T thru the gas in V to K while in the preceding figures the valve is primed with conductive current flowing from T to K. Fig. 8 is electrically equivalent to Fig. 4 with the addition to Fig. 4 of a capacitance connected in parallel with P. The capacitance between T and K is considered part of the capacitance C while the capacitance between T and the gas in V will be referred to as limitary capacitance be cause it limits the extent to which C can be discharged thru the gas in V. The damping of the circuit PC decreases as theratio of the limitary capacitance to the capacitance C decreases. The limitary capacitanceis a capacitance connected in parallel with C when the gas is ionized. The limitary capacitance is analogous to the stopping or blocking condenser in series with a detector connected in parallel -with the condenser of the secondary oscillatory circuitof a radio receivin circuit except as to comparative sizes. In this arrangement the oscillating current in P-C does not prime the valve; the valve is primed by a discharge in the circuit C-TK in which the inductance is very small or negligible and the capacitance is the limitary capacitance and C in series. The auxiliary oscillatory circuit PC will be referred to as the stabilizing circuit to distinguish it from the arc-priming dischar e circuit CTK. The current in G-T l is large, but the natural period of CTK is short, compared with circuit P- G. The priming discharge takes place when the positive charge on the terminal T pole of T1 is increasing it only partiallydischarges C, that is, C discharges thru C-T+-K until the charge of the limitary capacitance attains pratically the same potential as the charge on The priming circuit P-C in Figures 1. to 7 functions both as a stabilizing circuit and as an arc-priming circuit. The arrangement of Fig. 8 .functions better as a stabilizer because the efi'ective resistance ofcircuit P-"C is less;

a separate arc-priming'circuit is better because for a given amount of priming energy alarge priming current flowing for a short.

interval of time is more eflicacious in initiatmg the main discharge than a smaller priming current flowing for a longer in-'- terval of time. The priming energy required to initiate a discharge from A to K can'be made small if the frequency of the linear-sinusoidal oscillations is so chosen that the'potential of S is nearly high enough to cause a spark from A to K at the in- I stant of each cycle when the priming discharge takes place. The stabilizing circuit inductance P is coupled to L in such a way that the'priming terminal pole of C and the anode pole of S are simultaneously positively charged at a same instant of each cycle as the valve is being unprimed by means of the oscillation transformer 89.

Fig. 9 shows a modification of Figures 7 and 8. The condenser 17 is small com pared with C. P and C determine largely the period'of the stabilizing circuit as in Fig. 8. During one half of a cycle the condenser 17 is in parallel with C by current flowing thru the valve 16; during the make the inductance in the path of all current passing thru 17 as low as possible and introduce a resistance 18, if necessary, to make the current thru 17 non-oscillatory at the frequency of the local oscillations.

. The valves or arcs shown in Figure 1 to 9 have a common characteristic feature. In Fig. 1 assume S- charged to a potential which is high enough to spark across A-T, but not high enough to spark across A-T and T-K in series when the gas in T-K is not ionized. By impressing an E. M. F. across T-K from an auxiliary source whose positive pole is connected to T so that a spark passes from T to K the gas in T-K becomes ionized which allows the! condenser S to discharge. Similarly in Fig. 3 if S is charged to a potential insufficient to discharge across A--K a spark from T to K from an auxiliary source of high potential will allow S to discharge. Fig. 8 also illustrates this feature. With a. given potential impressed on A-K no discharge takes place, but by allowing sufficient displacement current to flow from the upper part of T to increase the ionization of the gas an auxiliary current Will initiate an arc dischar e of S by reducing the otential. require to spark from A to scribed above consists in -a-- (third) terminal in addition to the usual anode and cathode of an arc. Under given conditions a small expenditure of energy between this third terminal and the cathode will allow a, comparatively large amount'of energy to discharge fromA to K.. In Fig. 1 the third terminal consists of an additional anode and cathode, in Fig. 3 it consists of an additional anode and in Fig. 8 it 00111 sists of one pole of a capacitance while the opposite pole israrefied gas which becomes a conductor when it is ionized. These arrangements are well known, but no general term has been applied to them. I will refer to them as three-terminal arcs, or

three-terminal arc valves when-used for producing linear-sinusoidal oscillations, to distinguish them from two-terminal arcsas used in a class 2 are oscillator.

The difficulty of starting linear-sinusoidal oscillations will now be further considered.

Class 2 oscillations are started by means of class 1 oscillations which require an arc of drooping volt-ampere characteristic. The latter type of arc is ineflicient due to the large average voltage drop across the are and difiiculty in overcoming sluggish deionization of the as of the arc. An-arc in a vacuum, like t e mercury vapor arc, has a slightly drooping volt-ampere characteristic; class 1 oscillations which are sufliciently vigorous to 'lead to class 2 oscillations cannot be produced unless the effective resistance of the discharge circuit is very low; furthermore class 2 oscillations produced from a low potential source could not persist due to the high potential re-' quired to reignite the arc. If an automatic priming circuit is introduced then the oscillations can be made to persist.

It is desirable, however, to withdraw'energy from the discharge circuit while starting; or in. other words, to start under load. The objection to the method. of starting shown in Figures 4 and 5 has been noted.

Fig. '10 shows method of starting linear-sinusoidal oscillations. The stabilizing circuit is that shown in Fig. 8: The valve V differs from that of Fig. 8 in that it has a fourthterminal F which is also a priming terminal.

Inductance 20 and a condenser.19 a nected in series' between F and K condenser 19 is char edby means of the secondary of the trans orm'er or induction coil to a potential just high enough todi s charge condenser 19 across the gap F=-K.

The primary of 60 is connected in series with a source 61 of. direct current and a quick-break switch 62 which opens the pri-.

mary to the potential 7 required .to produce one train of oscillations in the starting priming a more practicable.

circuit of 60 and thereby charges-19 28, which circuit 19-F K-20. The natural time of the stabilizing circuit P-C."- The starting circuit oscillationsv produce linear-sinusoidal oscillations in L and S, which induce oscillations in PC; if the latter attain a sufficiently high amplitude the oscillations in the two interdependent circuit-s, viz, the stabilizing circuit and discharge circuit, will become self-sustaining. The damped train of oscillations in the starting oscillatory circuit must persist until the inertia of the direct current circuit has been sufliciently overcome in order to render the interdependent circuits self-sustaining. Since it is desirable to have the inductance I large it is necessary that the damping of the starting oscillations be low and their initial amplitude be high.

Figure 11.is similar to Fig. 10 except that an auxiliary source 63 of sustained alternating current is used for starting as in Figures 4 and 5. In this arrangement sustained alternating current passes between the terminal F and cathode K when, the quick make-and-break switch 64. is closed and opened. Any convenient source of alternating current of sufficiently high 'potential to sustain an are of proper current strength between F and K may be used. The frequency of the alternating current generated by 63 must practically equal the tween F and K should'be maintained only long enoughfcr oscillations in the interdependent circuits to reach self-sustaining amplitudes.

Fig. 12 shows an arrangement in which class 2 oscillations are produced in the priming circuit as in Fig. 2. A four-terminal arc is shown instead of the two arcs of Fig. 2. The capacity area 15 primes the primin terminal T which then rimes the valve with conductive current. The starting 05- cillations impressed on FfK produce simultaneously oscillations in L-S and in PC-. In this arrangement as in Fig. 2 the existence of oscillations in P-C does not depend upon oscillations in l L--S and the coupling between P and L.can be made zero if desired, provided the auxiliary direct current circuit rnishes enough energy for the priming cir- "tea. ,The current varying device 4 acts similarly as ing i fl ig. 2. The primingi terminal T may be placed over the cat ode as shown. 1 n v is a modification of Figures 8 and Fignifi 12. e-auxiliar .direct current :circuit is conductively insu ated fromthe principal direct current circuit by means of, condenser is largecomp'ared to C. The twotermin'al arcfl27 is of theusual class 2 are. oscillator .type. The coupling between L I sufiiciently high. To operate this arrangement impress a starting alternating current on F-K, separate the electrodes of 27 and then discontinue the starting current.

Fig. 14 shows an arrangement which constitutes a static direct current potential transformer. Secondary oscillatory and direct current circuits are added to the arrangements of Figures 10 and 11. The voltage of. S rises higher than that of E. With the switch 32 open the voltage of the secondary condenser Z will become practically equal to the maximum voltage of S 2y current passing thru the check valve 29.

current to flow 'thru the comparatively large inductance 3O and'thru the energy consuming device 31. S29--'Z constitutes the sec.- ondary oscillatory circuit. EI29-30- 31--32-L constitutes the secondary high potential direct current circuit. The in ductance of 30 should be greater than the inductance of I.

Fig. 15 is Fig. 14 modified by a difl erent connection between the low and high poten tial direct current circuits. The secondary inductance Q has been introduc'ed into the secondary circuits; this will increase the potential of Z. The valve 29 has also been connected to the cathode instead of to the anode of the valve; this allows the condenser S to be divided into two series condensers S and S The latter condensers conductively insulate the low and high potential direct current circuits, but electrostatically couple them. L-29-Z--Q constitutes the secondare on 38, The windings 39, 40, 41 and 42 are so wound that N is the north poles of the magnets. The windings 43 and 44 are so wound that while 43 is neutralizing 40 the winding 44 is assisting the winding 39. An alternating current of proper inaximum amplitude passed thru. 43 and 44 will cause the reed 47 to vibrate in synchronism with the frequency of the alternating current. The

' windings 45 and 46 bear the same relations to windings 41 39 and 4.0. v To operate this arrangement let the alternator 49 produce current of a frequency equal to the natural frequency of the circuit 45-"-46P--C. Close switch 50 and the reed will vibrate and alternately close and and 42 as 43 and 44 bear to ose 32 and the potential of Z will cause Linear-sinusoidal oscillations are thus produced in L and S from which energy is transferred to the 4546P-C circu1t, and the latter circuit then performs the function of the alternating current circuit which was used for starting the oscillations. The valve V prevents inverse discharge. The relative duration of broken and closed contact of 48can be adjusted to suit.

Fig. 17 shows another electro-mechanical arrangement similar to Fig. 16.- Two motors 53 and have a common shaft 54 on which is mounted a revolving contact maker 52 which is insulated from the shaft. 55 is a direct current motor and 53 is a single phase synchronous motor. The inductance of the winding of 53, the inductance P and capacitance C constitute an oscillatory circuit which determines the frequency at which 52 closes and breaks the discharge circuit. The are valve V prevents inverse current thru 52. This arrangement is operated by closing switch 50 which brings the motor 55 up to proper speed. Then open 50 and close 51 simultaneously. The linear-sinusoidal os cillations in L will induce sinusoidal oscillations in the synchronous motor actuating circuit P53-U. If the amplitude in the latter circuit is sufliciently hi h the two interdependent oscillatory circuits coupled by L and P become self-sustaining. Instead of opening 50, resistance 56may be introduced into the-starting circuit and the sychronous motor actuating circuit in conjunction with the startin clrcuit operate the revolving contact ma er. The brushes of the contact maker should be made adjustable for angular displacement with respect to the poles of the synchronous motor. a

Figures 16 and 1'? illustrate arrangements which do not require-the ignition or priming of an arc to close the discharge circuit in producing linear-sinusoidal oscillations. The expressions three-terminal and fourterminal arc must therefore be replacedby a more general term. The function of the arc is replaced in Figures 16 and 17 by a make-and-break switch and a check valve. A device by which one circuit closes, another circuit is called a relay. A device for discharging 'a Leyden jar is called a discharger. The expression unidirectional current relay-discharger will therefore be used to refer to a. device by means of which one circuit can discharge the capacitance of another circuit, prevent a reverse oscillatory discharge thru the discharger and open the latter circuit. The threeor four-terminal a'rciis a particular form of a unidirectional current relay-discharger. The

tance discharge teraeea discharger of a class 2 oscillatory circuit does not involve any relay function; The three circuits of a linear-sinusoidal oscillator will be'referred to as the direct current capacitance charging circuit, the direct current discharger circuit and the sinusoidal capacicircuit; the last two circuits being closed thru thedischarger.

Certain features which are common to the linear-sinusoidal oscillatory circuits shown will be noted. Resistances have not been shown in either the direct current line or in the discharge circuit. Itis understood that resistances or other energy consuming devices are introduced to limit the amplitudes of the current where necessary as is done in class 2 oscillatory circuits or other analogous circuits.

The coupling of priming circuit or stabilizing circuit to discharge circuit .has been shown as an inductive coupling. Direct coupling or other form of coupling can be used instead. The coupling between the interdependent circuits should always be a step-up oscillation transformer when the potential of E is low. During each cycle there is transfer of energy from L to P and retransfer of energy from P to L; the retransfer of energy should be made as small as possible in 'order to maintain the frequency constant and independent of direct current fluctuations. This can be effected by a change in coefficient of coupling, change in stabilizing circuit current amplitude and the ratio of the natural period of LS- to 19-0. To operate two oscillators in parallel from the same source of direct current the inductance I must be considered as part of the oscillator. Means for creating a magnetic field between the anode and cathode of the are and means for cooling the electrodes are not required as in class 2 are oscillators except at very high frequencies.

.Thermionic current oscillators have circuit arrangements which are analogous to my arrangements, but the valve is radically! difierent. An incandescent cathode, an

'anode and a control electrode or terminal constitute the essential elements of the valve. The cathode tends to continually ionize the space between anode and cathode while the control terminal either increases or, de=

creases this ionizing efi'ect depending o'n-thepolarity of this terminal with respect to the cathode. This type of valve has a rising volt-ampere characteristic and the cathode an incandescent filament which is fragile. Valves in which the incandescent filament has been replaced by an are have also been ience used with the arrangements of thermionic current oscillators. In the latter the function of the control circuit is the same as in thermionic current oscillators. For conven- I will refer to this class of valves as control valves in order to distinguish them from the valves of my arrangement,

which .I will designate discharge valves.-

The current thru a control valve follows at every instant the potential of the control terminal with respect to the cathode; the variations of the former are a repetition of the variations of the latter.- The current thru a discharge valve requires only to be started; after it has started it is independent of the potential of the priming terminal with respect to the cathode. The priming terminal 'acts as a trigger and cannot control the discharge after it has been started. The current thru a discharge valve produces its own ionization while in a.c0ntrol valve the ionization is produced by auxiliary means. The opening of the stabilizing circuitostops the linear-sinusoidal oscillations and flow of direct current while opening the litude of the potential of the control circuit '18 high enough linear-sinusoidal oscillations will result. The analogy between the arrangements of control valve oscillators and my circuit arrangements will suggest. many obvious modifications to the latter.

The Marconi and Franklin method de scribed in British Patent #7610 of 1913 shows an arrangement for producing linearsinusoidal oscillations by means of a threeterminal arc. The primary circuit is separately excited by a priming circuit whose natural period is less than the natural period of the discharge circuit, but the arc is primed at intervals whose durations is greater than the natural period of the discharge circuit. The natural frequency of the auxiliary or priming circuit is not the same as the frequency of the priming discharges which particularly distinguishes the arrangement from my arrangements. The .combined stabilizing circuit P-C and prim- 1n fu ther dist nguished by the presence of a limitary C is only partially discharged during each cycle of the linear-sinusoidal oscillations.

The arrangement used with the Uhafiee gap' illustrated in the Proceedings of the Institute of Radio Engineers,- vol. 42, page 343, is a linear-sinusoidal the antenna circuit may be compared in some respects to the stabilizing circuit of my arrangements. circuit which is a mainoscillatory circuit reacts uponthe discharge circuit and deterdischarge circuit CT- -K, Fig. 8, is capacitance and by the fact that' The current in the antenna oscillator in which able amplitude in the antenna circuit. In,

circuit. The rectifier and telephone receiver connected to the antenna circuit is analogous to the secondary oscillatory and direct current circuits.

- The illustrations have shown only the elements of my invention and not the details of construction which are understood to be sim ilar to class 2 arc oscillators, thermionic current oscillators and other analogous arrangements and devices. I do not Wish to be lim-' ited to the particular arrangements or devices illustrated and described except as required by my. claims.

I claim:

'1. In a linear-sinusoidal oscillator comprising a direct current capacitance charging circuit, a direct current discharger circuit,,a sinusoidal discharge circuit and a unidirectional current relay-discharger therefor, an auxiliary oscillating current relaydischarger actuating circuit coupled to said discharge circuit for actuating said relaydischarger of said oscillator.

2. In a linear-sinusoidal arc oscillator comprising a direct current capacitancecharging circuit, a direct current are circuit, a'sinusoidal discharge circuitand a unidirectional current relay-discharger therefor having 'a priming terminal and a cathode, an auxiliary oscillating current stabilizing circuit coup-led to said discharge circuit and connected to the priming terminal and to the cathode of said relay-discharger.

In a linear-sinusoidal oscillator comprising a direct current capacitance-charging circuit, a direct current discharger circuit, a sinusoidal discharge circuit and a unidirectional current relay-discharger therefor,

an oscillating current relay-discharger-actuating circuit'coupled to said discharge circuit and auxiliary means transiently op erative for producing currents 'in said circuits.

4. In a linear-sinusoidal arc oscillator comrising a direct current capacitance-chargng circuit, a direct current .discharger circult, a sinusoidal discharge circuit and an arc having a priming terminal and a cathode,

an auxiliary oscillating current stabilizing circuit coupled to said discharge circuit and connected to said priming terminal and to the cathode "of the arc of said oscillator and auxiliary means transiently operative for producing currents in said circuits.

5. In a linear-sinusoidal oscillator having a unidlrectional current relay-disc-harger and a discharge clrcuit, an oscillating current 'relay-dischargcr actuating circuit con-- charge circuit, a unidirectional current relaydischarger comprising rarefied gas in said discharge circuit, means for starting linearsinusoidal oscillations comp-rising asource of transient current and means for sustaining said oscillations comprising a source of sustained alternating current.

7. In a linear-sinusoidal arc oscillator having an arc and a discharge circuit, are terminals cons1st1ng of an anode, a cathode and a-prim'ing terminal and an auxiliary oscillating current stabilizing circuit coupled to the discharge circuit of said oscillator and connected to the priming terminal and cathaode ofsaid arc.

8. In a linear-sinusoidal arc oscillator, arc terminals comprising an anode, a cathode and a priming terminal, said'priming terminal consisting of a capacity area which With the cathode constitutes a capacitance, and an oscillating current stabilizing circuit connected to said terminal and to said cathode.

9. Ina linear-sinusoidal arc oscillator, a main discharge circuit, an auxiliary arcpriming discharge circuit comprising an arc and an oscillating current stabilizing circuit coupled to said main discharge circuit and to said arc-priming discharge circuit.

10. The combination of an arc consisting of an anode, an ionized gas anda cathode in series; an arc circuit comprising a source of direct current, an inductance and said are in series; a discharge circuit comprising a capacitance, an inductance and said are in series; a charging circuit comprising said source" of direct current, said inductances and said capacitance in series; an auxiliary oscillatory circuit comprising an auxiliary inductance and a second capacitance; a third capacitance and said ionized gas in series connected in parallel with said second capacitance; and, means for producing current .in said auxiliary oscillatory circuit.

11.. The combination of a circuit comprising a source of direct current, an inductance and an ionized arc-vapor conductor in series; a circuit comprising a capacitance, an inductance and said conductor in series; a circuit comprising said source of direct current, said inductances and said capacitance iii series; and, an auxiliary sustained oscillating current circuit coupled to, and excited by,

one of .said circuits and disposed to increase,

the ionization of said arc-vapor conductor.

linear-sinusoidal oscillations which consists in passing adirect current thru an electrical check valve comprising arc vapor and superposing upon said current flowing thru said valve a transient current of such amplitude that the resultant current flowing thru said valve becomes zero.

14. The method of starting and sustaining linear-sinusoidal oscillations which consists in starting linear-sinusoidal oscillations with a transient current superposed upon a direct current and sustaining said oscillations with a sustained alternatingcurrent.

15. The method of perpetuating a series of'linear-sinusoidal oscillations which consists in initiating each primed period of a series of linear-sinusoidal oscillations with an auxiliary oscillating current of constant amplitude, said initiationbeing effected during each cycle of said auxiliary oscillating current.

16. The method of producing constant amplitude linear-sinusoidal oscillations which consists in simultaneously partially discharging an inductance and charging a capacitance with direct current energy and with the energy of said partial discharge, discharging said capacitance thru an ionized gas, initially ionizin' said gas during each cycle of said oscill tions by means of an auxiliary oscillating current whose natural frequency is equal to the frequency of said oscillations and sustaining said auxiliary oscillat-ing current by means of said oscillations.

17. The method of initiating each discharge of aseries of capacitance are discharges thru a unidirectional current relaydischarger at the'resonant frequency of an auxiliary alternating currentcircuit which consists in charging a capacitance with energy from a direct current source, discharg' ing said'capacitance thru a unidirectional current relay-discharger and initiating each of said discharges by producing a priming discharge at the resonant frequency of an auxiliary alternating current circuit.

18. The method of keeping the time; in-

terval constant between the discharges of a capacitance thru a unidirectional current discharger which consists in charging a capacitance, discharging said capacitance by initiating a flow of current thru a unidlrectional current discharger with a constant amplitude oscillating-current and sustaining said oscillatin current by means of said capacitance dlsc arges.

19. The method'of controlling the time interval between arc discharges thru rarefied gas of a capacitance by means comprising an auxiliary capacitance which consists in charging said capacitance with direct current energy, discharging said capacitance thru rarefied gas, initiating each of said discharges by partially discharging an auxiliary capacitance thru said gas, and control-' ling the time interval between said initiatory auxiliary capacitance discharges by varying the frequency of an oscillating current.

20. A generator of linear-sinusoidal oscillations comprising a mam discharge circuit,

an oscillating current stabilizing circuit comprising inductance P and capacitance C and means for partially discharging said capacitance C to initiate each cycle of said linear-sinusoidal oscillations in said .main dischargecircuit, said partial discharge of capacitance 0 taking place in a circuit the natural frequency of which is higher than the natural frequency of said stabilizing circuit.

21. In means for producing linear-sinusoidal oscillations the combination of a discharge circuit, a unidirectional current relay-discharger in said discharge circuit comprising arc vapor, an auxiliary oscillating current circuit and means for actuating said relay-discharger at the natural frequency of said auxiliary oscillating current circuit.

22. In a generator of linear-sinusoidal oscillations the combination of a discharge circuit, a unidirectional current relay-discharger therefor comprising rarefied gas, a

stabilizing circuit comprising inductance and capacitance the natural frequency of which determines the frequency of said oscillations and means for transferring energy from said stabilizingfcircuit to said relay-discharger during each lations of said stabilizing circuit.

23. In means for producing linear-sinusoidal oscillations the combination of a'stabilizing circuit comprising inductance and capacitance, fied gas and an auxiliary discharge circuit cycle of the oscila conductor comprising rare- I charge circuit comprising means for partially discharging said capacitance during in order to start a train of each cycle of said oscillations.

25. In a generator of linear-sinusoidal oscillations the combination of a source of direct current, a rarefied gas container, means for establishing a direct current are thru the rarefied gas in said container and means for unpriming the are by reducing said direct current thru said are to zero for an instant said linear-sinusoidal oscillations.

26. The method of stabilizing linear-sinusoidal oscillations produced by means comprising a rarefied gas which consists in init-iating each cycle of linear-sinusoidal oscillations with an oscillating current and at the frequency of said current.

27. The method of reducing the potential of a direct current source required to sustain linear-sinusoidal oscillations produced by means comprising arc discharges thru rarefiedgas which consists in initiating each cycle of linear-sinusoidal oscillations by reducing the potential required to initiate an arc discharge once per .cycle of said oscillations with oscillating current energy.

HENRY G. CORDES. W'itnesses:

'1. M. LIBBY, R. N I'GHTINGAIE. 

